Glossary & Reference

The quick-reference page: the terms and formulas used across this course, with the locked numeric examples for fast recall.

Concept

This page consolidates definitions and formulas. It is a reference: use it while working, not as a first read.

Why It Matters

A single place to confirm "what does fz mean" or "what is n again" keeps decisions consistent and prevents unit errors on the shop floor.

How It Works

Key formulas

Core terms

Worked Example

Looking up "feed per tooth": fz is mm removed per flute; multiply by speed and flute count to get vf. The table gives the locked worked number so you can sanity-check your own calc.

Work the chain end to end. A Ø12 end mill at vc 150 m/min runs at n = 1000·150 /(π·12) = 3979 rpm. With 4 flutes at fz 0.05, vf = 3979·4·0.05 = 796 mm/min. If the machined surface measures 1.1 µm against a target 0.8, feed is too high for the nose radius: lower f or use a larger rε, using Ra = f²/(32·rε). Notice each quantity carries its unit through the chain — mixing mm/rev with mm/tooth is the most common arithmetic error on the shop floor.

More terms

Common unit conversions

Example: a catalog quoting vc = 400 SFM is about 400×0.305 = 122 m/min — close to the locked 120 m/min baseline, which is how you confirm an imperial table is describing the same steel cut. Always apply the conversion before plugging a number into a formula, and never mix an SFM value straight into n = 1000·vc /(π·D).

MRR and the power check

Material removal rate (MRR) converts a cut into volume per minute, which is what the spindle power actually has to deliver. In milling, MRR = ae · ap · vf (in consistent units, giving mm³/min, divided by 1000 to get cm³/min). Work the locked baseline: ae = 2 mm, ap = 10 mm, vf = 608 mm/min gives MRR = 2×10×608 = 12 160 mm³/min ≈ 12.2 cm³/min. In turning, MRR = ap · f · vc instead. The reason to keep this formula in the reference is that when the machine stalls or trips on power, the first question is not "is the tool dull" but "what is the MRR and does it fit the spindle" — which is the same tangential-force-to-power chain from page 04. If two setups remove the same volume, they demand roughly the same power regardless of how they are programmed; the tool choice only changes how efficiently that volume is cut. When the spindle stalls on a heavier pass, confirm the MRR before blaming the insert — an overloaded machine cannot be fixed by a sharper edge.

Use the glossary when a term is first used on a drawing or on the shop floor, and link the word back to its full page. A shared vocabulary prevents the kind of mis-order that happens when one person says "clearance" and another hears "tolerance". Keeping the terms precise is part of making the rest of the course reusable.

Common Mistakes

• Mixing mm/rev and mm/tooth. Fix: confirm the feed unit before using a formula.
• Forgetting units. Fix: always carry units through.
• Confusing accuracy with precision. Fix: accuracy is how close to true; precision is repeatability — see page 06 of the knowledge base.

Quick unit sanity checks

When a number looks wrong, check the unit first. Feed rate in mm/min and feed per rev in mm/rev differ by a factor of spindle speed; a "608 mm/min" at 3800 rpm is about 0.16 mm/rev — plausible. Surface speed in m/min must be converted to SFM by multiplying by about 3.28 when working from imperial data. Ra numbers below 1 µm are very fine finishes; numbers above 6 µm are rough. If your computed value sits far outside these ranges, the unit slipped before the arithmetic did.

Use this page as a quick lookup while you work, not as a substitute for the article behind each term. If a definition changes your decision, follow its link to the full page for the conditions, worked numbers and checks — a one-line glossary entry cannot carry the working-case detail.

Keep this page open while you work through the course rather than after it: each term links to the article where its conditions and worked numbers live. If a definition changes how you set a tool, follow the link and read the full case before committing the change to the machine.

Terms here are kept short on purpose; the depth lives in the linked articles.

Practice